Classification of scheduling problems and selection of corresponding constraint-based techniques

It has been argued that the use of constraint-based techniques and tools allows the implementation of precise, flexible, efficient and extensible scheduling systems: precise and flexible as the system can take into account any constraint expressible in the constraint language; efficient in as much as highly optimized constraint propagation procedures are now available; extensible as the consideration of a new type of constraint may require (especially in an object-oriented framework) only an extension to the constraint propagation system, or the implementation of additional decision-making modules (without needs for modification of the existing code). Yet there are a number of tradeoffs (between precision, flexibility, efficiency and extensibility) to consider when designing a scheduling system. These tradeoffs relate to: the representation of the scheduling problem; the set of control strategies to make available for the resolution of the problem; and the relation between the scheduling system and other information providing systems operating in the environment. Each of these three points suggests a different classification of scheduling problems and association of constraint-based techniques to scheduling problem classes